Insomnia symptoms, such as difficulty initiating or maintaining sleep, affect approximately ten million older adults in the United States. The presence of insomnia symptoms has been found in longitudinal studies to be associated with increased risks of depression, accidents, and falls and may lead to increased mortality. One major limitation of the current literature, however, is that objective measures of sleep derived by polysomnography have not been incorporated into large studies of insomnia outcomes in part because insomnia is largely a subjective diagnosis. However, polysomnography is necessary for the diagnosis of other common sleep disorders, such as sleep-related breathing disorder. This is especially relevant in older adults populations, where the prevalence of sleep-related breathing disorder may be as high as 25% and history/exam are unreliable indicators. The investigators of the current proposal have observed in prior research that comorbid insomnia and sleep-related breathing disorders may occur in 29% of older adults who present with insomnia symptoms. Furthermore, this comorbid state is associated with increased rates of functional impairment. Most concerning, however, is preliminary data that suggests that mortality rates in study participants with the comorbid state are higher than those with either condition alone. These findings have led the study investigators to hypothesize that comorbid insomnia and sleep-related breathing disorder is associated with significantly increased adverse outcomes relative to either condition alone. They have gathered extensive data from a case-control study of 200 older adults with and without insomnia that includes polysomnography and psychomotor assessments. They propose re-evaluating this cohort at an eight year follow-up period for the following specific aims: 1) to determine if insomnia and sleep-related breathing disorder are associated with increased degrees of functional impairment and mortality;and 2) to assess if the presence of co-existing sleep-related breathing disorder is a risk factor for persistence of insomnia complaints. This research proposal is consistent with the goals of an R21 mechanism in that it will gather exploratory data crucial to the design of future large studies in this area and it examines a disorder that has undergone limited investigation, thus it provides the opportunity to significantly expand our understanding of geriatric sleep disorders. Currently, insomnia and sleep-related breathing disorders are largely viewed as two separate clinical entities. If, as suggested by the preliminary data, comorbid insomnia and sleep-related breathing disorder are inter-related and lead to increased risk of adverse outcomes, the findings from this study will significantly alter the practice of sleep medicine and the care received by millions of older adults with sleep disorders. PUBLIC HEALTH RELEVANCE: Insomnia and sleep apnea (abnormal breathing patterns during sleep) are common in older adults and may each lead to increased risk of disease or death. Insomnia and sleep apnea may exist together in older adults in about 30% of cases and this combined state may be lead to significant adverse consequences;however, few studies have examined the long-term outcomes of this combined state. This research study will specifically explore these long-term outcomes to help establish the framework for future studies that identify effective methods to minimize these risks.